Variable Spring Supports and Hangers Properties

Note

Description

N210

Spring ignored as non-functioning. Upward spring travel from weight loads

Error occurs if, due to Piping weight, pipe displacement at the point where the support is installed is upward, which does not correspond to the principles of using variable spring supports. In this case, analysis is done without this support. You should remove it

N211

N535

There's no springs with appropriate flexibility in catalogue to satisfy load variation 25%, spring ignored. Please replace it by constant load spring

Displacement is so great. There's no such flexible springs in selected code to satisfy the specified load range limit (25% or 35%). In this case, analysis is done without this variable spring support.

It is recommended:

a) add more variable spring hangers nearby. Maybe software will select more flexible springs that satisfy allowable load requirement and load variation ration requirement

b) try to change the model or change the variable spring hanger placement to reduce the displacement range between operation and cold mode

c) replace variable spring by constant spring support

N688

Variable spring support unnecessary, loads are zero. Recommended to delete it

Variable spring support unnecessary at this place, because loads are zero. It is recommended to delete it

N298

Support with specified flexibility has not enough allowable load

Error occurs if support flexibility is specified by user, but actual load on the support exceeds the allowable load of springs corresponding to that flexibility value

W662

Specified load value exceeds the maximum load for the selected spring table or constant force hanger table

The maximum load on the specified spring or constant spring support is higher than the maximum value in the code table. There's no such springs or constant spring support in the selected spring table

W329

Allowable load of springs in the support is insufficient

This message appears

1. if flexibility (or stiffness) is input for a variable spring support or variable spring hanger, and that spring has a allowable load lower then the value obtained through analysis for operation and cold state. Allowable load is determined according to the springs database.

2. if flexibility (or stiffness) is not input, automatic spring selection is done, one of the criteria of which is meeting carrying capacity requirements in operation and cold state. Therefore, for models without non-linear effects (support friction, pendulum effect with hanger displacement, single-directional restraints) this check is always performed; while it may not be performed in the presence of non-linear effects. Load change (%) for the variable spring support or hanger should be reduced.

W101

More than two parallel spring rods selected because the load is too huge. It is recommended to add more variable spring hangers or switch to constant spring hanger

The load on variable spring hanger/support is too great. More parallel spring rods needed to hold it. It is recommended:

1. Add more variable spring hangers nearby. It will help to hold the huge load without increasing number of parallel spring rods

2. Switch to constant spring hanger. Some constant spring hangers can hold greater loads than variable spring hangers

W591

The number of parallel spring rods has been increased

The number of parallel spring rods in initial data was 1. But it was increased automatically up to 2. It could happen due two reasons: the load is too great and one parallel spring rod is not enough. And the spring stiffness may be too great and it should be lower to satisfy the requirement of variation ratio<25%

If two parallel spring rods can't be created then recommended:

1. Add more variable spring hangers nearby. It will help to hold the huge load without increasing number of parallel spring rods

2. Switch to constant spring hanger. Some constant spring hangers can hold greater loads than variable spring hangers

W661

Load range is greater than allowable 25% (35% for Russian springs)

It could happen due two reasons:

1. START-PROF failed to select spring that can satisfy requirement of load range ratio (R_op-R_cold)/R_op <25% (35% for Russian springs). The more flexible spring needed, but it is absent in selected code or more than two parallel spring rods needed to get more flexible spring. It is recommended:

a) try to add more variable spring hangers nearby. Maybe START-PROF will select more flexible ones that satisfy allowable load requirement and load variation ration requirement

b) try to change the model or change the variable spring hanger placement to reduce the displacement range between operation and cold mode

c) replace the variable spring hanger by constant force hanger, because it can be used with any load range ratio

2. Spring selection is done assuming absence of non-linear effects (friction, pendulum effect, etc.), and then re-analyzes the Piping considering non-linear effects. Therefore, load change value obtained through the analysis may exceed the input value. To improve it, the lower load range ration value should be specified in input data. For example the load range ratio could be specified 15%, 10%, 5% etc. until the load range ratio in analysis results become lower than allowable value 25% (or 35% for Russian springs). More...